The present invention generally relates to RFID interrogation systems and the ability to communicate with RFID tags associated with implantable medical devices (IMDs). More particularly, the present invention is directed to systems and methods for communicating with an RFID tag which is disposed in the hermetically sealed housing or can of the IMD.
There are known in the art various methods for identifying implanted medical devices. One such method is the use of X-ray identification tags encapsulated within header blocks of pacemakers or implantable cardioverter defibrillators (ICD). Such X-ray identification tags can be read on an X-ray of the implanted device and provide information to the physician. The information so provided is limited due to space and typically includes only the manufacturer and model number of the implanted device.
It would be beneficial if physicians were able to obtain additional information about an implanted device and/or a patient from an implanted identification tag. Such information would preferably include, in addition to the manufacturer and model number of the device, the serial number of the device, the date of manufacture, the treating physician's name and contact information and, if authorized by the patient, the patient's name, contact information, medical condition and treatment, and other relevant information concerning device programmed parameters and the like. There are many potential benefits from being able to determine the specific model and serial number and additional related device or patient information from an implanted medical device. For example, product recalls are an increasingly complex and extensive problem and the ability to rapidly identify the precise model and serial number of an implanted product may be life-saving. Cost savings for the involved company may also be substantial.
Currently, most implantable medical device (IMD) patients carry some sort of identification. This could be in the form of a card carried in the wallet or an ID bracelet indicating, for example, that they are a pacemaker wearer of a certain model and serial number. However, such forms of identification are often not reliable. It is quite common for an elderly patient to be presented at the emergency room (ER) of a hospital without his or her wallet and without wearing or carrying any type of a bracelet or other identification. In addition, there have been a number of situations where the patient (due to dementia or Alzheimer's, etc.) cannot clearly state that he or she even has a pacemaker.
Oftentimes the ER physician will palpitate the patient's chest and feel that there is an implanted device present. If the patient is comatose, has low blood pressure, or is in another form of cardiac distress, this presents a serious dilemma for the physician. At this moment in time, all that the physician knows is that the patient has some sort of an IMD implant. It could be a pacemaker, a cardioverter defibrillator, or even a vagus nerve stimulator, deep brain stimulator, or some other type of a growing range of passive and active IMDs. What happens next is both laborious and time consuming. The ER physician will have various manufacturers' cardiac rhythm management device (CRMD) programmers transported from the hospital pacemaker and ICD follow-up clinic or other site down to the ER. ER personnel will then try to interrogate the implantable medical device to see if they can determine what it is. For example, they might first try to use a Medtronic programmer to see if it is a Medtronic pacemaker. Then they might try a St. Jude, a Guidant, an ELA, a Biotronik or one of a number of other programmers that may be available. If none of those programmers work, then the ER physician has to consider that the implanted device may be a neurostimulator and try to locate a Cyberonics or Neuropace programmer.
It would be a great advantage and potentially lifesaving if the ER physician could very quickly identify the type of implant and model number. In certain cases, for example, with a pacemaker patient who is in cardiac distress, with an external programmer the physician could boost the pacemaker output voltage to properly recapture the heart, obtain a regular rhythm and stabilize blood pressure. All of the lost time running around to find the right programmer, however, may greatly delay or preclude this. Accordingly, there is a need for a way to rapidly identify the type and model number of an active implantable medical device so that the proper external programmer for it can be rapidly identified and obtained.
RFID tag implants have been previously used in animals for pet tracking. They have also been used in the livestock industry. For example, RFID tags have been placed in cattle to identify them and track certain information. However, the primary problem with using such prior devices in humans has to do with the fact that none of the current RFID tags have been designed to have long term reliability and biocompatibility within the body fluid environment. Methods used, include encapsulating an RFID tag in plastic or placing the RFID tag in a plastic or glass tube with an epoxy infill. However, none of these materials provide a truly hermetic seal against body fluids.
Accordingly, there is a need to identify and communicate with implanted IMDs. RFID tags can be used to communicate with IMDs and provide information relating to the IMD. However, there is a need for placing the RFID in a hermetically sealed environment to both protect the RFID tag as well as the patient. The present invention fulfills these needs and provides other related advantages.